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that occurred, 3) medication class, 4) prescriber type, and 5)
time of day the prescription was written.
Data collected from the electronic medical record included
a list of discharge prescriptions (drug name, strength, dose,
route, frequency, dispense quantity, number of reﬁlls), sex of the
patient, patient age, weight (in kg), time of day the prescription
was printed, and provider type. Prescribing errors were categorized into three broad categories (with subcategories also listed):
incomplete/inadequate prescription (directions missing/"as directed," directions unclear, quantity calculated in error, quantity
missing, quantity suﬃcient with number of days' supply not
indicated), dosing outside recommended range (below recommended dose, duration outside recommended range, over recommended dose, frequency outside recommended range), and
drug selection error (direction/dosage mismatch, dosage form
not available, not recommended for age, wrong dosage form).
One pharmacy intern and one clinical pharmacist reviewed
the discharge prescription list for errors following training in error identiﬁcation. Open-ended data were viewed by an additional
clinical pharmacist for agreement on categories. The ﬁnal prescription data set evaluated was compiled based on the majority's
decision of whether a prescription error occurred. The errors
were then evaluated based on the primary and secondary
outcomes listed above. Excel was used to evaluate data and
formulate results.

Table 1. Types of prescription errors detected
Errors
Type

Incomplete/inadequate prescription

78 58.2%

Directions missing/noting only "take as directed"

25 18.7%

Directions unclear

Quantity calculated in error

19 14.2%

Quantity missing

9.0%

6.7%

Quantity sufficient but no indication of number of days
Dosing outside recommended range

9.7%

27 20.1%

Below recommended dose

5.2%

Duration outside recommended range

0.7%

9.0%

Frequency outside recommended range

3.7%

Other (unable to find indication for nonprocedural use)

1.5%

Higher than recommended dose

Drug selection errors
Direction/dosage mismatch

29 21.6%
17 12.7%

Dosage form not available

4.5%

Not recommended for age

0.7%

Wrong dosage form

3.7%

RESULTS
Out of 1000 discharge prescriptions, prescribing errors were
present in 134 (13.4%). The number of prescriptions written for
adults and pediatric patients were 846 and 154, respectively. Of
the 134 total prescription errors, 35 (26.1%) were for pediatric
patients, which is an age group error rate of 22.7%. The adult
prescription error rate was 11.7% (99 prescriptions with errors
out of 846). The most common prescription error type was
"incomplete/inadequate prescription," with "directions missing/as directed" the most common subcategory error. The most
frequently prescribed medications that fell into this category
of error were prednisone, albuterol, and azithromycin. Table 1
shows the subtypes of errors detected, including frequencies.
Fifty-two classes of medications were prescribed. The drug
class with the highest number of prescription errors was antibiotics, resulting in a within-class error rate of 14.9%. Within
this category, errors were found most frequently in prescriptions
written for azithromycin and amoxicillin. Azithromycin errors
found were "directions missing/as directed," "quantity calculated in error," "directions unclear," or "duration outside recommended range." Amoxicillin errors found were either "quantity
missing" or "quantity suﬃcient but with number of days' supply
not indicated." Eleven of the 23 antibiotic prescription errors
were for pediatric patients. The medication classes with 50%
or higher within-class error rates included antianginal medications, antiparasitic medications, antacids, appetite stimulants,
probiotics, nebulized medications, and insulin. Table 2 lists the
frequencies of error rates by drug class.
Forty-four individual physicians wrote ED discharge
prescriptions. EM attending physicians and residents were
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responsible for 40.3% of the total errors that were identiﬁed.
The error rate was 6.1% for EM attending physicians, 9.2%
for EM residents, 69.2% for non-EM attending physicians, and
20.9% for non-EM residents (Table 3).
The average rate of prescriptions written per hour over the
study period was 6.9, with rates increasing around 10:00 am,
peaking at 2:00 pm, and decreasing around 8:00 pm (Figure 1a).
Most prescription errors occurred between 10:00 am and
6:00 pm (104 errors, 77.6%), and particularly between 2:00 pm
and 3:00 pm (22 errors, or 19% of all prescriptions written)
(Figure 1b).
DISCUSSION
This study shows that nearly 14% of discharge prescriptions
written in the ED contain medication errors. The ﬁnding that
nearly half of the errors in antibiotic prescriptions were for children is concerning. The potential for underdose or overdose is
present and can impact the patient response and recovery for the
condition for which the antibiotics were prescribed. Reasons for
incorrect dosing of an antibiotic may be due to incorrect weightbased dosing or simply not being able to visualize the label
comments or handwritten edits on "take as directed" antibiotics.
The type of error that occurred most frequently was missing
directions or simply noting "take as directed"-which was also
found in a study conducted by the Institute for Safe Medication
Practices (10). Many patients may be unable to remember speciﬁc administration directions given by a practitioner without
written instruction as a backup. Similar to the study by Bizovi
et al (11), medication prescriptions with ﬁll-in prepopulated

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